THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

ERIN BURNETT, CNN HOST, OUTFRONT: So the fear has been that he is armed and dangerous throughout the day, that he could have explosives on him. It is possible, however, possible, that he does not.

THOMAS FUENTES, CNN CONTRIBUTOR: Well, in this case, it sounds like the people that have a visual on him have a pretty good look at what he's doing, if they are indicating, they don't think he has a suicide vest or explosive vest or if he doesn't have guns or if he doesn't have a hostage. If they have that kind of a view of what he does have or doesn't have, then you know, it would add to the confidence level of how to handle him as a barricaded subject.

And again, after that shootout when he takes off on foot, he probably didn't take the time to unload that truck and run down the street carrying pipe bombs and guns and gas masks and explosives and everything else. We're hoping. We're hoping that that would not be the case, if he is running for his life last night, after the gun battle with the police.

ANDERSON COOPER, CNN ANCHOR: That's Tom Fuentes, formerly with the FBI, who has been monitoring this for us.

Anderson Cooper here, taking over our coverage. I'm here with John King and Deborah Feyerick.

If you are just joining us, this is a pivotal moment in this manhunt that we have been monitoring all day long. Authorities believe they have a possible suspect surrounded, located in a structure. We are not going to go into further detail than that for tactical reasons.

We have reports -- Deb, what are the latest reports about flash- bangs?

DEBORAH FEYERICK, CNN CORRESPONDENT: Latest report is that they have deployed several flash-bangs from the ground, we are hearing about eight and some of those could be echoes. But, they have deployed a number of flash-bangs and they are getting ready to deploy gas as well. They really want to stun him because they just don't know what kind of state of mind he's in. He may be desperate. Somebody today described him as a cornered cat that he's desperate and you don't know how he will strike out.

So, they're trying to proceed with as much caution as they possibly can to take him alive, but also to make sure there's no loss of life. And we're told that right in the vicinity of where they've got him, there's also sort of a 40 gallon tank. So, they are going to be very careful about that as well. They don't want to fire a random shot and have something happen there.

COOPER: But at this point, John King, with night falling, night is actually to the advantage of law enforcement personnel. They have night vision goggles. They can control the night and if they want, frankly, they can light up the scene.

JOHN KING, CNN CHIEF NATIONAL CORRESPONDENT: And they believe they have a tactical advantage this time as opposed to last night when they were surprised and the suspect escaped. Did you believe they have the great tactical advantage right now and they want to take their time, a, because of the risks to law enforcement, b, the risk to the neighborhood and c, because they are now amassing overwhelming presence to the point, Anderson, that they have essentially eye contact. They have visual contact with this believed to be the suspect. And there are reports going in and among law enforcement on the scene as well as back to state officials, city officials, as far back as the justice department, the FBI in Washington, trying to coordinate now the next move.

So yes, they believe they have a tactical advantage. They brought in extra units, military style vehicles in case there are explosives there. They have lighting and night vision equipment and the like if they decide to use that. And the question now is they believe time is theirs, that they have him trapped. However, they also have memories of what happened last night.

COOPER: I want to bring in Jeff Beatty, a security consultant formerly with the FBI and also with CIA counterterrorism official.

The authorities, if they have a perimeter set up, they can take their time on this.

JEFF BEATTY, FORMER FBI SPECIAL AGENT: Exactly. What's the rush at this point. They are saying, fools rush in. Don't need to do that. We talked earlier about waning light. That's actually an advantage to the security forces. They get to pick, do we want to use bright light, do we want to completely take the light away from the entire block and take advantage of our night vision goggles.

You know, you are right on with multiple flash-bangs being used. That's appropriate to disorient him, to continue to disorient him, to deaden his ear drums so he can't hear the footfalls of those approaching him. The hard cover provided by the military vehicles, other hand-held hard cover they can move into position.

You know, I train the FBI's hostage rescue team when they first came down to delta to get their national level hostage rescue 101/102. And there are times in an operation like this where you go quickly and there are times when you stop and regroup and you say, can now we do a bit of a deliberate modification to our plan. It's all about preserving officer safety, preserving safety of the folks in the neighborhood. And of course, in this case, they do want to take him alive because he will be a treasure trove of information. So that's some of what's going on right now.

COOPER: It is interesting. We have been seeing house-to-house searching all day long, obviously. Elizabeth Cohen reporting she spoke to somebody in this neighborhood where this operation is going on. We are not going into any more specifics on that. But that person, that neighbor, said that that person's house had not been searched. So clearly, there are some areas which have not yet been searched. This is a large area and for all the large number of law enforcement personnel that we have seen, they have been very methodical today having to go house to house, door by door, block by block.

BEATTY: And a decision could also have been made, you know, as they evacuate people and they have isolated and they know what's clear and what's not clear, to back off a little bit and give the individual an opportunity to try to move or let down his guard, but they have been very effective. And, you know, I think that they are going to be very deliberate as they go forward here and I'm optimistic that the odds are in their favor now to be able to pick him up alive if in fact this is the individual.

COOPER: Right. And we should stress, we don't know that for a fact. Law enforcement is saying they believe a possible suspect. How confident are you hearing from your sources about the identity?

KING: They are quite confident. They have the suspect and they engaged the suspect including with some gunfire. Did they wound the suspect? We don't know. But there was gunfire at the scene and then once they did surround the area, they have a visual contact on the suspect and there have been reports back of movement.

At one point there was an indication of some law enforcement originally on the scene radioed back they believed the suspect was down. But then, as they brought more to the scene, they have visual contact of the suspect moving. I just talk to a federal source a moment ago who said that those reports have ceased in terms of the movement has ceased. That doesn't mean anything. It could mean, just still.

And so, as this plays out, they now are convinced that they have total visual environment. They are trying to evacuate any residents in the area from the neighborhood. And as was noted, now they went to move, the flash-bangs, be methodical. The one thing, they're not certain, Anderson. They are not certain, but they are operating under the assumption there are explosives in that yard.

You know, I think one of the best examples for your viewers, I'm sure many of them saw "zero dark thirty." there was an initial assault phase, helicopters crashing in and all, then it seemed like minutes went by as people then started deliberately moving through and that's kind of a parallel to what you're going to see happen here tonight. But I think within a few hours of darkness, this could be favorably resolved.

BEATTY: You know, I think one of best examples for your viewers, I'm sure many of them saw "Zero Dark Thirty" and there was an initial assault-face helicopters are crashing and all and it seem like minutes went by. And as people then started deliberately moving through. And that is kind of parallel to what you are going to see happen here tonight.

But, I think within a few hours of darkness, this could be favorably resolved.

COOPER: One of our producers, CNN produce Lawrence Crook, is near the scene.

Lawrence, what are you seeing? What are you hearing?

LAWRENCE CROOK, CNN PRODUCER (via phone): Well, I'm at Washburn and Chester street which is about a block from Franklin Street where I'm told from a Boston police source that they have a suspect cornered in the backyard of a home.

I'm also told that they're using flash-bangs to try to get him out. The number one priority for the police is to try to get this guy out alive. They would like to see him go to trial. And I'm also amazed at the amount of neighbors that have gathered around this area. Probably about 30 to 40 people that are just sitting here in awe.

I have only been here for about 20 minutes. Within the first five to ten minutes I heard anywhere from six to ten small explosions which I later found out were flash-bang grenades. It's really a fluid scene. I'm so close that the helicopter overhead, I can hear the explosions going off as the helicopter's directly above. It's just amazing. Flashing lights, I have never seen anything like it.

COOPER: We should point out for our viewers, and we have had this information awhile but for tactical reasons we have not been reporting it. But now, we are confident we can say we believe the suspect is cornered in a boat. This is a small boat which is in a backyard.

FEYERICK: Correct. It was in dry dock at the time. And one of the concerns, Anderson, is that they have -- there's a house right next to the boat and there was a family inside the house. And when we were talking about the fuel, we were talking about is there fuel in the boat. They believe it's a 40 gallon tank so they have to be very careful about that. But, that's why he was able to get inside.

COOPER: Drew Griffin who is in Watertown initially heard the exchange of automatic fire which kind of alerted us to this uptick in the kinetic situation.

Drew, what are you seeing where you are?

DREW GRIFFIN, CNN INVESTIGATIVE CORRESPONDENT: Just I want to button up some of the continuing coverage here. David Fitzpatrick saw those people evacuated. Police officers running out with small children. Those -- that family, there's about ten people, they didn't speak very good English, but they said they were indeed evacuated. They all looked fine. They didn't want to talk on camera, but they were literally in their house, they heard all these gun shots. Next thing you know, the police are telling them to get out and raced them out.

The one man did confirm there is a boat kind of in dry dock or on a trailer, I couldn't understand him correctly, in the backyard. So that's, I just wanted to button that up that those people are fine even though it was a somewhat dramatic escape as the police were getting them out -- Anderson.

COOPER: OK. Drew, appreciate that update.

John King, your sources tell you there had been an engagement of fire. Does that mean on both sides, this suspect, possible suspect, had fired back?

KING: Don't know the answer to that. I was just told by a federal law enforcement official that officers on the scene had engaged an individual they believed to be the suspect they were looking for. And then at that point, they had trapped in the backyard and when they believe there was no -- he was not escaping, they were told to just keep their positions and wait until bomb squad and more responders and some other tactical forces could arrive, again, because a, they want to overwhelm him in terms of numbers but also get protective gear and heavier gear in the event there are explosives.

COOPER: And I believe we are going to show the boat from our affiliate -- actually can't see it in that shot, but I'm told.

FEYERICK: I think it's way back at the end of the driveway there. You can see it. Looks almost like a motor boat.

COOPER: From WCBB, just a small shot of it. Small shot of it there.

It is interesting, you know, there is still a lot to learn obviously about whether there are other people involved in this operation, whether or not they had some sort of help, logistical help, operational help. We simply don't know.

But, what is interesting, Jeff, I would love your perspective on it, for two people, two individuals who seem to have case out the bombing site, planned this out with some level of planning, they don't seem to have -- did not seem to have much of an end game. They did not seem to have an escape route. They do not seem to have money. They do not seem to have a plan.

BEATTY: Exactly. You know, we talked about this a little the other day. You know, there was a mixture here of good execution and sloppiness, you know, just a mixture of that evidence here which tells me that maybe later, we'll find out that the training that these individuals had was maybe done remotely through the Internet, et cetera and it focused on actions at the objective, but it didn't focus on well, what do we do after that, how do we move?

You know, you mentioned a bit about maybe there's other people involved. One of the questions I have is, you know, we, law enforcement has gone to the apartment. They have found explosives, additional explosives. We know there was another pressure cooker that was thrown in the chase last night. So, that either tells me that they had a plan to do additional targets, or in fact, there were additional participants for whom these weapons were manufactured who for one reason or another were not available on the day of the marathon or, you know, maybe they were going to use them later.

COOPER: Also, surprising, our Chris Lawrence, who has been on the campus where Dzhokhar attended classes at the university of Massachusetts at Dartmouth, students there have seen him over the last several days going to the gym, just being on campus.

FEYERICK: And we know that investigators were actually there because they were looking for an individual who is a friend of the younger brothers. And so, that was one of the reasons that you saw a heavy presence there.

But, that's a big question that investigators are asking themselves. Why if they had such a good plan going into this attack, why didn't they have an equally good plan getting out of the attack. And one of the hypotheses is that in fact, somebody was supposed to help them, somebody was supposed to provide them money or help them get out and somehow that person failed.

And so, that's a big part of the equation because even though the device was crude, it was sophisticated enough to detonate and that's why you speak to these experts, and they say frankly, it's the first successful attack of its kind in America since 9/11.

COOPER: We obviously don't want to go down the road too far speculation of other people being involved these days. There's so much we don't know at this stage about their motive, about their operational capabilities, about their planning, how long they had been planning this.

But, we do know is a possible suspect. Authorities according to John king's sources, believe with some certainty that it is a suspect number two, the 19-year-old Dzhokhar, who they have been looking for since last night, since these photos were released, cornered in a boat.

Can you explain, Jeff, flash-bang grenades. And we talk about this. We have seen them in movies. How do they work and why would they be thrown now, if the operator's not moving in?

BEATTY: Well, they might -- first of all, the way they work, it's a device that doesn't really have any shrapnel. It has some powder that's designed to burn brilliantly and burn quickly. Pull the pin just like a regular grenade, you throw it and it's got about a two-second delay, then you can adjust the delay before it goes off. It's designed to achieve surprise if you have to enter a room right behind it where there might be armed opposition.

But why would they use it now? We've talked about movement and then no movement. You know, I mean, if you throw these into the area, it might provoke movement. Maybe they're concerned as to, is the individual actually still conscious or alive, for that matter. And so, the throwing of these flash-bangs in close proximity to them -- I tell you what, I've been on the receiving end of these things in exercises and it's very hard to stay still when one of these things go off around you. And it also, it would not kill the individual so it would preserve their ability to take him alive.

COOPER: So, in addition to stunning them, in addition to stunning them, stunning him if he is alive, if he does not move, that might give them some indication as well --

BEATTY: Some indication that perhaps unconscious or something.

COOPER: Elizabeth Cohen is standing by in the area.

Elizabeth, I know you have been talking to people in that neighborhood. What are you hearing?

ELIZABETH COHEN, CNN SENIOR MEDICAL CORRESPONDENT (via phone): Yes. The neighbors here have congregated about half a block away from where this house is that seems to be an interest. Several hundred neighbors -- some of them seem quite angry. They say that their houses were not inspected, no one told them to evacuate, knocked to their door. In fact, I spoke to the next door neighbor right next to the home where it appears they think the suspect might be, and she said nobody knocked on her door, no one searched her home, and then she found that sort of alarming. This woman is quite concerned about because her children are home with her parents and she can't get to them. We also just saw paramedics walking in the direction of the house where police seem to be looking at the suspect.

COOPER: Elizabeth, stand by. Want to bring in Jason Carroll.

Jason, explain in a general sense where you are and what you're seeing around you.

And Anderson, I have to tell you, when we got here, we were talking to neighbors who talked about hearing about 20 shots and as we saw a huge police presence here down the street, we moved back. Helicopter overhead. And then, just about 15, 20 minutes or so, we heard that loud, very loud flash-bang that we've been hearing people talk about.

Shortly thereafter, Anderson, it was about, I don't know, a minute or so of no activity, no sound, and then we heard what appeared to be several shots. That sound sounded different than the flash- bang. I have heard one of those before and it distinctively sounded different. It was definitely shots being fired. And then, there was another brief moment when there was silence, no activity. And then, again, we heard what appeared to be, what may have been another flash- bang being shot off as well.

Again, I'm in the area of Mount Auburn and Bailey road, and there are a number of neighbors who are out here. They are being kept back. (INAUDIBLE) are still here, still very, very heavy. When we initially got here listening to some of the police officers coming out, telling us to get back, that there had been a cross-fire situation, no further explanation in terms of what that meant. We were held back here, again. At this point, neighbors standing around waiting to be told what to do. But again, heavy police presence as we are standing here at this corner, waiting to see what is going to happen next.

COOPER: We are trying to check in with all our people all throughout the region, trying to get as many eyes on this as possible. Brian Todd is standing by on the phone.

Brian, what are you witnessing and hearing?

BRIAN TODD, CNN CORRESPONDENT (via phone): Anderson, we are behind the house on Franklin Street, some distance away, probably 300 yards away from a boat in a backyard that's being floodlit by law enforcement officers. They are yelling loudly to someone either in the boat or near it, come out, and we just heard them say come out on your own terms. We also heard them say come out with your hands up. We were -- we got a little bit closer than we are now before we were waved away by law enforcement officers. We are being told now we have to cut out of here but we have a clear view of a boat that seems to be shrink-wrapped in some plastic, where they are focusing lights and we can hear officers yelling at someone who is either inside the boat or near it.

COOPER: Brian, how long ago were the officers telling the suspect to come out?

TODD: How long ago where the officers telling the suspect to come out?

TODD: That was literally, Anderson, probably three minutes ago. We are now being pushed back by law enforcement. We are fading back a little bit behind a dumpster. But we are going to stay as close as we can. This is, clearly, they have floodlights on this boat. They are yelling at someone who is either inside it or near it. They seem to be trying to talk to that person.

COOPER: Brian, you just tell me whatever you're seeing and hearing as you're hearing it. But can you give me a sense of -- you said they have lights on the boat. Is the entire area kind of floodlit? How lit up is it?

TODD: The entire area is not floodlit. They just have lights on the boat. There is shrink wrap kind of blowing in the wind around the boat. They have lights on it. We took some footage of it and we did hear them talking very loudly to the person involved. We are being pushed further back by law enforcement right now.

We were actually warned when we got to this back alleyway, this parking lot behind the house, when law enforcement officers saw us first, they told us to get back because we are in the cross-fire area.

COOPER: Brian, and again, you may not have the answer to this, but when officers were yelling at the suspect, to your knowledge, was there any response back?

TODD: We could not hear any response, Anderson. We heard them speaking to him fairly continuously. We did not hear any response. We did not hear any of the flash-bangs or anything like that. We may have gotten here after the reports of that happened. We have not heard any gunfire or flash-bangs. But we did hear someone speaking very loudly to whoever was either inside or very near that boat.

COOPER: David Fitzpatrick, CNN producer, is also joining us on the phone.

David, you were one of the first on scene reports we had of officers moving in with guns drawn. What are you seeing now from your vantage point?

DAVID FITZPATRICK, CNN PRODUCER: They are (INAUDIBLE).

COOPER: David, we're having a problem hearing you on your cell phone. We will try to get a better connection. Call us back as soon as you can.

So, Jeff Beatty, you heard from Brian Todd, officers trying to establish communication, trying to tell the suspect to come out. We don't know if there has been any response.

BEATTY: Of course, that is the best way to go, to get him to walk out. That is the way to go. He can come out with his hands raised, they can get a good visual on him to make sure he's not wearing anybody-worn explosives or something like that. So that is obviously the best way to go. Hopefully that will be successful.

COOPER: There had been reports about his brother being found with explosive devices on him. Have we confirmed that?

FEYERICK: The brother definitely had explosives on him. As a matter of fact, we're told by a source that in fact, there was a trigger mechanism as well.

COOPER: Do we know the specifics on that trigger mechanism?

FEYERICK: We don't. And that's what's of key interest. Where it came from and that could tell also the signature of the device, where he learned how to make it.

COOPER: Which obviously would be incredibly important for law enforcement personnel now to know, not only whether or not he has a device on him but what sort of trigger mechanism because even if he has his hands up, if he has a trigger mechanism in a hand, that can be deadly.

BEATTY: Right. And often there's like a dead man switch that people use, if you release it, it's like stepping off your riding lawn mower. It automatically flips the circuit, and then, the vest would detonate. So, they definitely want to be on the lookout for that.

That's why we heard reports of having people disrobe partially or completely, you know, earlier in the day when there was a concern that perhaps they were wearing a body-worn explosive. That's common tactic over in Afghanistan, when you are concerned that that might be the case, and it makes a lot of sense to do it here when you're worried about it.

COOPER: From a tactical standpoint, is there any way to prevent that? I mean, is it -- I've always been told a head shot is the only way, but --

BEATTY: When you're trying to capture him alive, to get the information that you really do want to get, one of the things you can do is you can make good use of canines, explosion detection canines. You can send a canine up there. I have trained canines that are good enough to go off leash and go up there and they will sit on him if he is wearing an explosive, they will alert on it. So that will also give you an indicator that there's an explosive involved. I know they got some good canines in this town and that's a possibility as well.

COOPER: And you have no doubt, given the lack of information that everybody has about the suspect at this point, they would like to capture him alive, just not only from a justice standpoint but just from even an intelligence gathering standpoint.

BEATTY: Yes. I think that we want to know how this happened. You know, our national, our department of homeland security wants to know how this happened. The FBI wants to know how this happened so that we can keep similar incidents from happening in the future. He's a big key to that. So it would be advantageous to get him alive.

FEYERICK: Yes. And one thing we are going to say that is so interesting is that the older brother really seems to have been the ringleader on all of this. And I think John was reporting something similar. And that is, this is an individual who we know went to Russia back in January 2012, he stayed for six months. What he did there, there's speculation that perhaps he may have gone and gotten some training there.

COOPER: Bottom line, we do not know what he did there. But we do know the FBI spoke to him subsequently at the request of a foreign government.

KING: At the request of a foreign government. They had some conversations with him. We are trying to get more details about why -- just exactly why was the foreign government interested, which foreign government was it, if possible. That will be all part of the lessons learned, if you will, and the further intelligence gathering after the fact.

There's two giant concerns right now. One is the immediate one, to get the second suspect hopefully into custody but certainly, to get the second suspect off the field, if you will. And then, they will go back and look at the lessons learned and those will be the questions raised. Did they miss any flags with this guy, or where did that information come from?

And to Jeff's point specifically, when he did leave the country, what specifically was he doing. Was he trained by somebody else. Was this training they got on their own because it is sadly available on the Internet. Those are questions they very much want to answer. But, they have an immediate concern this evening.

BEATTY: And you know, it's interesting to me to look at even the names of these young men, you know, Tamerlan, probably Tamerlane, a great Islamic warrior who had many campaigns that resulted in the deaths of millions of people. And also, you know, the young brother, Dzhokhar, named after the similar name, anyhow, to the first president of the Chechen Republic, the Islamic republic, that was formed there.

So, I don't know if there's anything about identity when you're given a name like that as a youth, what kind of, what does that do to your mindset and your self-image and your identity, what's expected of you. Interesting to hear the profilers talk about that.

COOPER: It is very interesting, this 19-year-old who we believe is the suspect now cornered, authorities believe with some level of confidence that is who they have cornered in this boat, in this small boat in the backyard. We know he came to the United States at the age of 8-years-old back in 2002, I believe it was. His brother, who died last night, died at the age of 26, came four years later, I believe at the age of 20, did not himself become a U.S. citizen but did get a green card.

BEATTY: But you know, the fighting in Chechnya really started in '94 and didn't end until 2009. So during their formative years, you know, they have seen patrols, they have seen armed action most likely.

COOPER: Well, although actually, one uncle said that the younger son had never actually even really been to Chechnya as an adult. So, we don't know what the older one, whether he has or not.

BEATTY: They were there in their early years.

COOPER: Yes.

FEYERICK: And the one thing we also want to make clear is, we are not 100 percent sure whether in fact they ever became radicalized, why they did this. The motive is still very uncertain.

We are also told that they lived on the border of Chechnya. That it wasn't Chechnya proper. It was the Russian caucus. But, clearly, they had a key identifier with that country.

So, all of this is under investigation as to what may have motivated them, why all of a sudden the older brother seemed to feel so passionate perhaps about the country. All of that is under investigation.

COOPER: There have also been several movements in the surrounding republics around Chechnya, and even up until very recently, there had been some killings in some of the republics as well that have been causing concern.

Again, a lot happening at this hour. This is video that was taken earlier. Obviously you can tell by the light. It is now darkness here. But this, you see tactical units, heavily armed SWAT units, moving in toward the area of this house.

I mean, Jeff Beatty, formerly with the FBI, also CIA counterterrorism official, with some confidence, the police must feel pretty good about having a secure perimeter around this scene.

BEATTY: I'm sure they do, but I'm sure they will also be cautious about the potential to booby-trap the location as he took cover there within that boat. So he may have booby-trapped the local area so they want to be cautious again, good use of canines or robots and canines to go ahead and make sure as they make their approach. There's no rush. They can be deliberate. He's not going anywhere. They do have it well contained.

COOPER: Also joining us by remote is Bob Baer, formerly CIA officer with extensive experience in the Middle East, throughout the world.

Bob, as you watch this operation unfold, and when you hear the information from several sources that a foreign government did request that the FBI interview the older brother, I believe it was back in 2011, if I'm not mistaken, after he returned from Russia. Do you see that as very significant or is that the kind of thing more routine?

ROBERT BAER, CNN CONTRIBUTOR: No. That's significant. It was probably the Russians came to the CIA or the FBI and said look, we think this guy may have been recruited, what's he done, where has he been, what's his status in Massachusetts.

The Russians are really in control in terms of intelligence of the north caucuses, whether it is Dagestan or Chechnya. They have the expertise. They speak the languages. The CIA and the FBI have pretty well stayed away from these regions because they are so complicated. They haven't been a threat to date. And so, we defer to foreign governments.

Now, we don't entirely trust the Russians on this because he may have simply been a political dissident but nonetheless, it's indicative, we're looking at an organization behind these two boys.

COOPER: The Chechens were obviously involved in taking more than 100 people hostage in that Moscow Theater. There was also the incident, taking over the school in Beslan, the school in Beslan. There was also, obviously the Chechens had been fighting in the war in Bosnia in the early '90s. I remember seeing them in and around Sarajevo back in '93, '94, even now in Syria, there are reports --

BEATTY: And Afghanistan.

COOPER: And Afghanistan, certainly.

David Fitzpatrick, our producer is on the scene. David, what are you seeing again?

FITZPATRICK: Anderson, (INAUDIBLE) they are some ways in back of the property. I see armed agents, police, FBI, their guns still resting on the fronts of their cars. I see about half a dozen, maybe eight guys in SWAT uniforms, military SWAT uniforms, at the bottom of the house.

But, Anderson, I have to tell you. It is pretty quiet here for the past half hour or so. As I earlier reported, residents were led out and sometimes carried, little children carried by officers to safety. They were obviously residents of nearby houses.

But right now, it's almost eerie. There is nothing here. Quiet and settled over here. There are parked fewer officers. I must also note, when I first arrived, there must have been more than 200 here. So they have obviously gone elsewhere. Right now, fairly quiet here.

COOPER: Brian Todd had reported from about I think he said 300 yards away from another location with eyes on the scene, that authorities had actually -- were shining lights on the boat where this suspect is believed to be.

Not sure of the level of intensity of the lighting in this region, but also, as Jeff Beatty had been talking about, they could also be using night vision equipment to their advantage if they so choose. They clearly have a lot of things at their disposal.

BEATTY: They have time on their side, as has been mentioned. I think that asking him to come out, trying to talk him out, I wouldn't be surprised to soon hear police megaphones being used to make sure they can communicate with him.

COOPER: This may be a dumb question but after you have thrown multiple flash-bang grenades, can a suspect actually hear you?

BEATTY: Yes. It only stuns you for a few seconds then your hearing will slowly come back. You may have a ringing in your ears depending upon how close it is but you'll be able to hear.

COOPER: I want to go back to Brian Todd, just down the street from the standoff. Brian, I'm not sure how close you are at this point. I know you were being moved back for obvious safety reasons. What are you seeing now?

BRIAN TODD, CNN CORRESPONDENT: Well, Anderson, we were moved fairly far away from the perimeter by the police. They rushed toward us when we were about I'd say between 200 and 300 yards away. We're not able to get a visible sign of it right now, but we're trying to move into some position where we can.

What we did see was the floodlit boat. We could hear officers yelling loudly at the person who was apparently inside. What my team and I heard was come out on your own terms, come out with your hands up.

They would alternate floodlighting the entire boat, a couple of times, just for a few seconds, they would floodlight the entire backyard and then they would leave it dark for a few seconds. It was kind of sporadic. But at that point, we had police rushing toward us telling us to push back because we were in the cross-fire area.

COOPER: So about how far now are you from the location of the boat?

TODD: I'd say we're probably 400 to 500 yards away from it.

COOPER: OK, we'll continue, stick with us, Brian. If there's any new movement or sounds that you hear, let us know. Elizabeth Cohen is about four houses down from where this standoff is taking place. Elizabeth, what are you seeing?

ELIZABETH COHEN, CNN SENIOR MEDICAL CORRESPONDENT: Anderson, there's an accumulation of police. There's got to be well over 100 police and FBI right now. Also an accumulation of ambulances, police cars, SUV, commissioner of the Boston Police Department just came and shook the hands of some of his officers, and then left.

What I'm hearing from residents is that they were just sort of surprised that they expected that their houses would have been inspected, they would have been told to evacuate and the ones living right here in this area, some of them said that that didn't happen.

And they were surprised by that. But we're seeing more and more police showing up and moving us a little bit further back as well.

COOPER: Jeff, for law enforcement personnel, this has been an extraordinarily difficult day, because in order to search each house it's not just a matter of knocking on a door. You have to assume at each structure that the suspect could be there, could be armed, and could have some sort of explosive devices.

BEATTY: Or could have a member of the household hostage, telling the person that answers the door you're going to tell him I'm not here and everything is fine. One of the other things that's possible is if they had an inkling that the suspect may be where he currently is, perhaps they didn't want to heat that area up too much.

And wanted to back off a little bit, cause some relaxation then in a more subtle way, try to evacuate residents so that those residents weren't put at risk from being in kind of a final firefight. So we'll have to see what their thinking was later on.

COOPER: In terms of the timeline of this, obviously this all began sort of from our vantage point, coming on our radar with reports of a robbery at a convenience store in Cambridge around 10:00 last night, about 20 minutes later, police responded to the scene nearby, found an officer shot in his vehicle, shot dead, an MIT police officer, 26 years old.

Then a carjacking about 30 minutes later, the owner of that car was released unharmed, but a chase then ensued, ended up in Watertown, where there was an exchange of gunfire, some explosive devices as well. One suspect, suspect number one, was shot dead. From earlier reporting, you stop me if this is not correct, his brother actually drove over his body at least according to one report?

COOPER: What is not clear is what happened between that point? He clearly got away from that exchange in a vehicle. Do we know anything between that moment and this moment?

FEYERICK: No. That's still very murky. Still very murky as to how his brother ended up in a place where police could get him and the younger brother fled. We believe that the younger brother fled on foot.

And that's why this morning when they went in, this massive police presence when we got there at about 4:00 this morning, they had a 20 block radius that was completely sectioned off.

And you had every sort of military gear, you had the helmets and people stationed almost 20 feet apart, people stationed 20 feet apart and they were all watching and almost choking off this one area.

COOPER: In addition, later in the day, several hours ago, we learned that a number of officers actually received injuries. I believe the number if memory serves me correct was about 15. We know one officer was severely injured, underwent surgery, is doing better right now, I believe.

That was the last update I heard. But 15 officers had received some level of injuries which raises the question, did this suspect, suspect number two, this 19-year-old, Dzhokhar, did he actually receive some injuries and again, to that we don't know.

FEYERICK: They believe that he may have been injured. They do believe he may have been injured. We heard all day reports about a trail of blood. We couldn't get anyone to say there that was his or his brother's blood. They are working under the assumption he was indeed injured. That's why they figured if they had him rest, that they would maybe flush him out on their own.

COOPER: Susan Candiotti is standing by, on the street where -- Susan, are you where the initial exchange of gunfire took place in the early morning hours yesterday in Watertown? Where are you exactly?

SUSAN CANDIOTTI, CNN NATIONAL CORRESPONDENT: In that immediate area, yes. But right now, we're in the spot where as soon as David Fitzpatrick heard those shots, the gunfire, at this spot, which is another staging area, we saw all kinds of police activity pick up.

There was almost a roar of people listening to what was going on. You could see something was up. I will never forget this sight, at that time a number of squad cars came through as well as police vans and SWAT teams, and one of them had the back doors literally flying open.

And you could see inside the SWAT team members hanging on it seemed for dear life and all of them went sailing up there. Since then, things have gotten much more quiet here. We're far enough away that we cannot hear those flash-bangs or the gunfire, but they have had an ambulance standing by here. They have bomb squad truck standing by here.

We have seen city buses full of police officers being taken in and coming back out again. And of course, we can also see a bit of the smoke and police helicopters going by occasionally. So here we have a spot where, like in so many other places, you have neighbors standing by as well. Yes.

COOPER: Susan, for our viewers who are not from this region, again, it's very confusing to get the logistical layout of all this from an operational standpoint, but from that engagement that occurred in the early morning hours yesterday in which suspect number one was killed, in that standoff with police, to where we now believe suspect number two is cornered, how far away are those distances?

CANDIOTTI: Well, it's almost like a triangular distance, I would say. Maybe Drew could help us out a little more precisely, because he was here at that exact moment. But I think that where we are now is in the general area, anyway, of where that chase wound up. So they could give you a little more precise on that. But I know this is one of the staging areas where we have been throughout close to where all that came down.

COOPER: Sorry, Susan. I'm just receiving information.

CANDIOTTI: That's OK.

COOPER: Go ahead, Susan.

CANDIOTTI: I was just going to say, when we were here throughout the day, you know, the streets were barren. It was eerie and surreal. We drove around and you could see all kinds of, as you know, police activity throughout the day as they were conducting searches.

COOPER: Susan, I just got to jump in. I've just received this information. This is from CNN New York, from Jason Kesler. While executing a search warrant in New Bedford, Massachusetts at a residence believed to have been affiliated with Dzhokhar Tsarnaev, the FBI took three people, two males and a female into questioning Friday evening.

This is according to New Bedford Police Lieutenant Robert Richard. The resident searched by the FBI is private off-campus housing for U-Mass Dartmouth students. While executing a search warrant in New Bedford, Massachusetts, this at a residence that is believed to have been affiliated with the suspect, 19-year-old Dzhokhar Tsarnaev, in the past.

The FBI took three people, two males and a female, into custody for questioning Friday evening, according to New Bedford police. The residence searched by the private off-campus housing of three students. There have been questions throughout the day.

I talked to Chris Lawrence about this, whether or not the suspect, Dzhokhar, was actually living on the U-Mass Dartmouth campus or whether he was at this residence that was being searched throughout the day in Cambridge. It doesn't seem like we really know one way or the other.

JOHN KING, CNN CHIEF NATIONAL CORRESPONDENT: We should be careful in the sense they have been taken in for questioning. They're going to retrace every step as they look through every e-mail, cell phone conversation, every place he's lived in recent years, friends, and family members. They are going to question everybody.

Now we wait to see from the FBI, New Bedford police saying they were taken in for questioning by the FBI. We'll see whether they are persons of interest or they are just trying to get information about where he's been in recent days, who he's been in communication with, any indication of threatening behavior or unusual behavior.

That's part of a normal investigation. Three people in a private residence taken in for questioning, not all that surprising, key question is are they expanding the net or do they think the two brothers acted alone.

COOPER: We also know there are a number of family members. The mother is in Dagestan with the father, but the mother has lived here and the father had lived here on and off as well. There is also I believe two sisters, at least one of whom is married, I believe perhaps both are married, but again, we don't know the full details on the family dynamics at this point.

Again, Susan Candiotti was just telling us, again, Susan, I'm sorry. I was reading that e-mail. I know you said it was in a triangular area, but can you give a sense in blocks about how far away, what I'm trying to establish is how far he may have gone after that shootout early morning to the location where he is believed to be now. Do we know about how far?

CANDIOTTI: You know, I think it's around a mile or less than that, but I'm not absolutely sure about that. But that's what I keep directing you to. Drew might know the answer. I just wanted to add with the questioning of other people, remember, late this afternoon we were also told that so far, they had no evidence of any accomplices, no evidence of it so far.

But obviously as part of the investigation, they certainly want to talk to whoever knows him, who hung out with him, friends of his, to see what information they could gather. Obviously they are also trying to track down where he was.

COOPER: Susan, also, it was reported several hours ago that police did confirm they found a number of homemade, described as homemade explosive devices in various scenes in Watertown, where the exchange of gunfire had been and explosives, correct?

CANDIOTTI: That's right. They haven't been precise about that, in terms of defining what they meant by that, but clearly, it would include all the homemade pipe bombs.

COOPER: Susan, I got to interrupt. I want to go to Brian Todd. Brian, what are you hearing? TODD: Anderson, we are on a rooftop, I can't say where it is. We have a visual on the boat. Too far away to hear -- we do have a visual --

COOPER: Brian Todd, I don't know if -- we can't hear you, Brian. I don't know if you're on the move. Let's go to Elizabeth Cohen. Elizabeth, what are you hearing and seeing?

COHEN: Anderson, I'm not sure exactly what just happened, but the police here erupted in applause. The police car came out and took a left and headed down the street. Someone yelled out is that him and the police officer said yes. That's all I know. That's all I can tell you from here. I don't know if it means there was a definite round of applause from police as the car drove away. As the police car drove away.

COOPER: Did you see anybody, the obvious question. Did you see anybody in the back of that police car?

COHEN: You know, impossible to see. It was totally dark. It was impossible to see.

COOPER: What is the situation now?

COHEN: The situation now is that everyone, fire truck or ambulance, went in down the street towards the house that we've been talking about. So a police car came out and police applauded as it left, and then another vehicle, what looked like a safety vehicle or perhaps an ambulance, went in down the street.

COOPER: So it is right now 8:44 p.m. here in Boston. All of this began almost, well, 22 hours ago. Go ahead. Are you hearing any more, Elizabeth?

COHEN: No, I'm not hearing anymore. I'm not hearing anymore. That happened, and the police, they look a little more relaxed. It looks a little bit different than it did before.

COOPER: Just to repeat, who said, did you get -- who spoke to police, who said what?

COHEN: The residents, several hundred residents are at this corner and they yelled out to the police is that him, is that him. One of the police officers said yes. The residents started applauding even more.

I don't know if the police officer really understood what the question was, but there was applause among the police and applause among the residents here at the corner here. Again, I'm just painting a picture here describing the scene.

I'm not entirely sure what this means but there was again, a police car drove out and down the street.

COOPER: At 8:45 p.m. in Boston, applause from the police, residents saying to police did you get him. One police officer saying yes, a vehicle driving away. That's all the information we have. Deborah Feyerick, John King with me. Deb, what are you hearing?

FEYERICK: This is a fascinating e-mail coming from Chris Lawrence, who is on the U-Mass Dartmouth campus today. Apparently, officials are confirming a "Boston Globe" report that he was on campus on Wednesday.

That apparently a swipe card shows that he entered the building and he went to the gym and spent Wednesday night in his dorm on campus. That's coming from Chris Lawrence. That's been approved by folks in Washington.

COOPER: Again, around 8:45, the most clear word or most positive word we have gotten from one of our -- Boston police have just tweeted suspect in custody. Let me repeat that. Around 8:45 p.m., Boston Police Department has just tweeted that the suspect is in fact in custody.

This seems to verify what Elizabeth Cohen witnessed, neighbors yelling at police did you get him, police officers saying yes as the vehicle drove off. It's safe to assume that the suspect is in that vehicle. What happens now?

JULIETTE KAYYEM, CNN ANALYST: Well, now we're in the sort of usual criminal legal process. This is a big debate in counterterrorism, whether our courts can handle terrorism cases. They can. This is going to be a long legal proceeding with lots of evidence, if he is well enough to survive whatever happened. It sounds like he was. So part two is now the continuing investigation and now the legal case, which will be a year or two ahead.

COOPER: If you're just joining us, good evening, everyone. What started about 23 hours ago now seems to be finally over. The last suspect being searched for by police, according to Boston Police Department, that suspect is now in custody.

Our Elizabeth Cohen is on the scene in Watertown where the suspect had been surrounded for the last at least hour or so, seeing a police vehicle driving off. Policemen breaking out into applause. Neighbors asking the police has the suspect been taken. One police officer saying yes, he has.

Now the Boston Police Department actually tweeting out that the suspect is in custody. I'm joined by John King, Deborah Feyerick, and Juliette Kayyem who has worked in homeland security here in Massachusetts.

We got a report just a short time ago there was an ambulance on the scene. He seems to have been taken away in a vehicle, not in that ambulance. We don't know if he needs medical attention or not. We do not know his status.

That's been one of the questions all day long. A number of police have been injured just in the melee in the early morning hours in Watertown. We know one police officer obviously was killed.

Another one was seriously wounded, went into surgery, but as many as 15 had received minor injuries and are doing OK. We don't know what his status is. Assuming he's not physically hurt, where will he be taken?

KAYYEM: Right now, he will be taken to the U.S. attorney, to our federal courthouse which is about two miles away from here, three miles away from here. He'll be booked and processed and arrested and if this is going to start a very unusual day will start to look very, very usual. We will determine whether he will get legal counsel. He will get a defense attorney and then therefore, the case proceeds.

KING: From a federal law enforcement official, being told the suspect is alive. He has unspecified medical needs. We have to see what those are. It could affect whether it's the courthouse or whether you get medical treatment at another site.

According to this federal official, an aggressive sweep of the scene is underway to see if there are explosives on the site. He was taken out of the boat without incident.

They are having everything in the area, including the SWAT team, the bomb teams, the sniffer teams, to make sure they don't have a volatile, dangerous crime scene environment.

This suspect is alive, has unspecified medical needs and according to that federal official, an aggressive sweep of that scene under way.

COOPER: I can tell you the police officers standing a little bit further down from the block certainly seem a lot more happy right now at this moment, the least tense that we've seen them all day long.

No doubt, the city of Boston, Watertown, all surrounding areas, a lot of people breathing a big sigh of relief. The hope, of course, now that the suspect is in custody, is that authorities have actually the right people.

Jeff Toobin is standing by, senior legal analyst. Jeffrey, from a legal standpoint, assuming this person needs medical attention, what happens now? As the wheels of justice begin to move?

JEFFREY TOOBIN, CNN SENIOR LEGAL ANALYST (via telephone): The first thing that will happen is that the U.S. attorney's office will prepare a complaint, which will be an affidavit by an FBI agent, which will lay out the basics of the case against him. He will then be arraigned.

He will get a defense attorney and he will have an arraignment. In normal circumstances, someone arrested on a Friday night would probably not be arraigned until Monday morning. Just because of the extraordinary circumstances here, he might be arraigned tomorrow if he's in medical shape to be arraigned.

At the arraignment, two things will happen. There will be a discussion of bail. He will not get out on bail, obviously. But they will set what's called a preliminary hearing 30 days forward. The preliminary hearing will not happen. What will happen is in those 30 days, in the next 30 days, he will be indicted by a grand jury with the initial charges. Then the case will be assigned to a federal district judge and that's when the case will really begin.

But the next legal event will be an arraignment, perhaps tomorrow, perhaps Monday, in any case, at a time when he's physically able to be arraigned.

COOPER: So at this point, I assume, what, he's been read his Miranda Rights and at what point does he get counsel?

TOOBIN: He will get counsel more or less immediately, if he asks for it. Certainly he will be read his Miranda Rights. This is obviously a very controversial subject involving terrorism investigations, but since this was an FBI arrest, this will -- he will be read his Miranda Rights.

He doesn't have to ask for a lawyer. He could make statements that could later be used against him. That's after all what the Miranda warnings are. You can have an attorney or you can make a statement depending on --

COOPER: Jeff, let me jump in here. I want to check in with John King.

TOOBIN: -- he will either speak to --

COOPER: John, you're hearing more?

KING: I just want to pass along information from our producer, who says two federal law enforcement officials have confirmed to her they have verified the identity. It is the younger brother, suspect number two, in custody.

It is now they say federal officials verified the identity and have no doubt. As I said earlier, a federal official I communicated with said in custody, unspecified medical needs and they are now sweeping that scene to make sure there are no additional risks.

COOPER: Brian Todd is standing by. Brian, what are you seeing, what did you see go down?

TODD: Anderson, we just observed the scene from a rooftop probably 500 yards away from the backyard area. It had calmed down but we did see police activity in the backyard. Flashlights moving around, a police chopper had returned to the scene. It visibly calmed down.

They were not floodlighting the boat anymore, but they did have a dimmer light on it and police and possibly vehicles had come to the back area. There seems to be some kind of alleyway or something behind that house. So we did see that activity from a rooftop. Then police came and moved us off the rooftop pretty quickly.

COOPER: It is the end. It is the end of this massive manhunt that has been going on now, this operation that began 10:00 last night with the first reports of a robbery at a convenience store in Cambridge, Massachusetts. What a 23-hour period this has been. Tom Fuentes, formerly with the FBI, is standing by monitoring all of this with us as well. Tom, your thoughts at this moment?

TOM FUENTES, CNN LAW ENFORCEMENT ANALYST: Well, Anderson, I just wanted to give you one possible scenario, which actually occurred in the Abdul Mutallab underwear bomber case. After he was taken off that airplane in Detroit, he was provided his Miranda Rights by FBI agents who were going to begin the interrogation.

He waived his rights so they began to interview him. He required medical care because he had burned his legs in the process of trying to set off the device so they accompanied him to the hospital. He got all the medical treatment that he needed and then they gave him his Miranda Rights again and the interviews commenced again.

He agreed to cooperate and that total interview I think was about 14 hours before he was finally, you know, had had enough and took it in. So if he wants to waive his rights, he doesn't immediately have to be booked and get a defense attorney assigned.

Again, we don't know exactly how severe his injuries are. I would think they're not that severe. They had an ambulance at the scene. If he required that degree of medical care, he would have been transported by ambulance rather than by police car.

So in this case, it's really going to depend on what his attitude is when the agents try to talk to him. They'll give him his rights. If he says I'm exercising my rights, I'm not talking then it's over.

They'll go to the next step. He'll receive his medical treatment and then be booked and get a defense attorney, but if he waives his rights, that changes everything.

COOPER: I want you -- let's put up that tweet from the Boston Police Department, this, the official confirmation. You see it. Suspect in custody, officers sweeping the area. Stand by for further information.

Juliette Kayyem, it is an extraordinary moment. Let's take a moment to think about this. What began, this nightmare that began Monday night now seems to be over, at least this initial phase of it, the manhunt.

Obviously, the investigation continues. But what a victory not only for law enforcement but also for the citizens of this city who not only stood tall in the face of terrorism, but who also sent in videos, sent in pictures, and were instrumental in catching these suspects.

KAYYEM: Right. This was so unique in the sense of how the citizens and the public were utilized to get information about the suspects, to begin the investigation, to possibly, we still don't know whether the press conference, I'm forgetting my days now, whether the press conference where the FBI released the pictures, resulted in this manhunt that night.

But we have to assume that there is some relation between the FBI crowd sourcing and all the information coming in, plus people staying inside. I want to make it clear what that was about. Because there's a thought that he was so dangerous that everyone was going to be a victim.

That is just not true. That was to relieve public safety officials to let the successful manhunt continue, because people were not out on the street, he could hide -- he could only hide. He could not be walking around. That's clearly what happened. So that is good news.

The 6:00 p.m. conference today in which they said all clear, government officials, is probably in my professional judgment not related to what happened about an hour or hour and a half later. You wouldn't tell citizens to come out and then in Watertown say go back in, because we're in a shootout. I think they were unrelated.

COOPER: Susan Candiotti is standing by. Susan, what's going on where you are?

CANDIOTTI: Well, you see the ambulance and bomb squad trucks leaving to applause from people who are standing by. Look at all these people in the neighborhood. They are giving applause and waving and smiling, as soon as everyone got word that the suspect is in custody, the same thing happened.

Police officers shaking hands with each other, smiling, you can see what's going on here now, as more and more police cars are pulling out of this area. Clearly it's over and people here are very happy that they will be able to go back to their lives -- Anderson.

COOPER: I don't know if we still have Bob Baer standing by, but from an intelligence standpoint, there are still so many questions to be answered, Juliette Kayyem. Obviously this is one aspect of this investigation which is done. The safety of the city is now much clearer, but now a whole other -- many other arms of this investigation continue.

KAYYEM: There's a confirmed report about this New Bedford arrest and search. New Bedford is a southern coastal town from here. We'll see where that leads, but the idea that this is over is not true.

COOPER: OK. What we're looking at is the boat. We believe the suspect was on the boat when this picture was taken. This is the boat. This was taken a short time ago. Again, you can see one helicopter lighting up the scene as Brian Todd had been talking about.

But again, when these images were taken, we believe the suspect was still in the boat. You can see some of the tarp, the shrink wrap that was on the boat that had apparently been lifted off.

We're not sure whether that was by the suspect or law enforcement but clearly, as Brian Todd has been telling us, they had lit up that boat very carefully. This after a number of flash-bang grenades had already been thrown.

Because Brian Todd reported he himself did not hear the flash- bang grenades and got on to the scene shortly after the flash-bang grenades had already been detonated.

FEYERICK: One thing we are learning is that there were injuries, that he was injured, so we are being told that he is with FBI agents and he's either at Mount Auburn or Mass General is where he's being taken with injuries.

COOPER: OK. Our full coverage is going to continue. I'll be back for another edition of 360 at 10:00 p.m. Eastern. I will stay here on the ground. Our coverage continues right now with "PIERS MORGAN LIVE" -- Piers.